Many types of systems are known for effecting material handling and processing operations, particularly in the case of materials consisting of sheet or sheet-like material units such as documents, mail pieces, inserts, papers, envelopes, and the like. These systems are often arranged in a series of different apparatuses or devices that perform specific handling and/or processing operations. Such operations can include bulk loading, singulating, registering, sorting, staging, accumulating, folding, printing, shearing, merging, envelope stuffing, envelope wetting, envelope sealing, and combinations thereof. Moreover, the systems define one or more flow paths for one or more streams of material units or sets of material units. Given that many different operations can be performed on one or more streams of material units, the various operations and their respective apparatuses must be coordinated through timing and synchronization while maintaining a commercially acceptable level of throughput.
In some of these operations, two or more sheet streams must be merged into a single stream. One example is the processing of two-up material, which typically is provided on a 17 inch continuous roll. The width of the roll is such that two 8.5×11 inch printed pages are disposed in adjacent relation to each other. Several side-by-side pairs of such pages are contained in succession along the length of the roll. The pages are individualized in separate sheets and sheet streams by using one or more cutting devices.
A staging module is typically used whenever an application requires that one or more sheets in one or more process streams be paused or held for a certain period of time while other operations are performed, initialized, or reset. In operations such as those briefly described above, the use of a staging module can be useful for assisting in the synchronization of the various operations being conducted on the sheets.
Material units such as document sheets can be categorized as being either “flats” or “letters.” In this context, a flat unit is a material unit that remains planar at the end of each processing operation—that is, the unit is not folded. A letter unit, on the other hand, is folded one or more times by some form of a folding apparatus. Conventional sheet handling systems require two separate and distinct modules to handle flats and letters, respectively. This is largely due to the fact that flats and letters are dimensionally different from each other and is especially true with regard to staging, accumulating, and collecting modules. Indeed, flats and letters are conventionally handled by two entirely separate handling systems. For material unit processing sites that conduct processing jobs on both flat and letter-type units, the deployment of separate modules and/or systems requires a large overall machine footprint and thus costly floorspace.
An apparatus that functions as a document collector, diverter and stager is disclosed U.S. Pat. No. 5,899,453, commonly assigned herewith and the contents of which are incorporated herein. The apparatus is capable of collecting sheet articles, selectively diverting or advancing the collected sheet articles, and holding or staging the advanced sheet articles until a predetermined time when they are then selectively further advanced to a downstream module such as an envelope inserter. First and second stages include transport mechanisms for advancing sheet articles through the apparatus. Each transport mechanism includes a pair of rotation members such as endless belts or chains that rotate around arrangements of rollers. Each pair of rotation members are driven independently from the other pair, so that sheet articles in each stage can be processed selectively and independently of the other stage. For instance, as sheet articles in the second stage are being advanced therefrom, sheet articles could be collecting in the first stage, or a collected stack of sheet articles could be held or staged in the first stage. In a preferred embodiment, plastic chains are provided with plastic lugs attached thereto for engaging the sheet articles. An example of a suitable lightweight chain and lug arrangement is disclosed in U.S. Pat. No. 5,806,659, commonly assigned herewith and the contents of which are incorporated herein. The sheet articles processed by the apparatus disclosed in U.S. Pat. No. 5,899,453 can be either folded or unfolded. The apparatus, however, does not provide a means for adjusting between a flats mode specifically designed to handle unfolded articles and a letters mode specifically designed to handle folded articles.
It would therefore be advantageous to provide a unitary module or apparatus that is capable of handling both flats and letters without adversely affecting the efficiency of the processing jobs to be conducted. Such an apparatus would reduce the footprint required at the processing site, and be easily adjustable or convertible between the two modes of operation, i.e., between flat and letters processing. Moreover, such an apparatus should be compatible with existing upstream and downstream modules ordinarily provided with sheet handling systems.
The present invention, as described and claimed hereinbelow, addresses these and other problems associated with the handling of different types of material units.